Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

To detect new odors, fruit fly brains improve on a well-known computer algorithm

04.12.2018

New framework discovered by Salk scientists could improve machine-learning methods or help to detect when novelty detection is impaired in the brain

It might seem like fruit flies would have nothing in common with computers, but new research from the Salk Institute reveals that the two identify novel information in similar ways. The work, which appeared in Proceedings of the National Academy of Sciences (PNAS) on December 3, 2018, not only sheds light on an important neurobiological problem--how organisms detect new odors--but could also improve algorithms for novelty detection in computer science.


This image of flies buzzing around glasses of wine illustrates how flies detect novel odors using a tactic similar to that of a computer using a computational tool called a Bloom filter. In the fly version, neurons called Kenyon cells in a region of the fly brain called the mushroom body (MBON-a'3) process olfactory information and broadcast a 'novelty alert' signal when a new odor is encountered.

Credit: Salk Institute

"When a fly smells an odor, the fly needs to quickly figure out if it has smelled the odor before, to determine if the odor is new and something it should pay attention to," says Saket Navlakha, an assistant professor in Salk's Integrative Biology Laboratory. "In computer science, this is an important task called novelty detection. Understanding how novelty detection strategies compare in both domains could give us valuable insights into both brain algorithms and computing." The researchers suggest that their new framework could be useful in detecting duplicates or anomalies in large, streaming data sets, such as patient databases or news stories.

In 2017, Navlakha discovered how fly brains identify similar odors. He found that applying the fly algorithm to computer "similarity searches" (such as ones that suggest products to buy that are similar to your past purchases) improved the search results.

The new PNAS study is based on another paper [Hattori et al.] that came out in 2017 in the journal Cell, describing how flies detect entirely new odors. When Navlakha read the study, he was struck by how the flies seemed to be using a tactic similar to a computational tool for novelty detection called a Bloom filter.

When a search engine such as Google crawls the Web, it needs to know whether a website it comes across has previously been indexed, so that it doesn't waste time indexing the same site again. The problem is there are trillions of websites on the Web, and storing all of them in memory is computationally expensive. In the 1970s, Howard Bloom at MIT devised a data structure that can store a large database of items compactly. Instead of storing each item in the database in its entirety, a Bloom filter stores a small "fingerprint" of each item using only a few bits of space per item. By checking whether the same fingerprint appears twice in the database, a system can quickly determine whether the item is a duplicate or something novel.

Fruit flies are well known to change their behavior in response to novel odors. A region in the fly brain, called the mushroom body, contains a collection of neurons that processes olfactory information. When a new odor is experienced, these neurons broadcast a "novelty alert" signal so the fly knows this odor is new and worth investigating. If the odor, however, does not have a strong impact, the next time the odor is experienced, the strength of the alert signal is reduced and the fly doesn't waste time investigating the odor. This is an important computation because the fly wants to pay attention to something only if it's worth it. The fly's mushroom-body novelty signal is generated using a fingerprint for odors akin to the Bloom filter's "data fingerprint."

"A fundamental challenge in machine learning is finding representations of data that are suitable for a wide range of tasks," says Sanjoy Dasgupta, a professor of computer science and engineering at UC San Diego and the new paper's first author. "The fly's olfactory system shows us one simple and ingenious way of doing this."

By analyzing--from a computer science perspective--the neural circuit, identified in the Cell paper, that generates this novelty signal, Navlakha and Dasgupta found that the fruit fly introduced a couple of new twists to the traditional Bloom filter, which their team elaborated and defined mathematically.

The first twist involves not just determining whether you've smelled the exact same odor before, but rather if you've smelled the odor, or something pretty similar to it. This is important in the brain because chances are that you'll never smell the exact same odor twice. The second twist involves determining how long ago you've smelled the odor. If it's been a long time, then the odor's novelty should be higher than if you've smelled the odor rather recently.

Based on the fruit fly's Bloom filter variant, the team created a new algorithmic framework to predict fruit flies' novelty responses. They tested their framework on research data collected as flies were presented pairs of odors in succession. The team's novelty predictions turned out to closely match the actual novelty response of the mushroom body neurons, which validated their framework's accuracy. Navlakha's team then tested the framework on several machine learning data sets and found that the fly's Bloom filter improved the accuracy of novelty detection compared to other types of novelty detection filters.

Navlakha adds, "What makes this work especially exciting to us is that it represents one of the first data structures discovered in the brain, along with a simple algorithm for how the brain may actually perform novelty detection."

###

The work was funded by the Pew Charitable Trusts, the Kavli Institute for Brain and Mind, and the NIDCD of the National Institutes of Health under award number 1R01DC017695.

Other authors included Timothy C. Sheehan of UC San Diego and Charles F. Stevens of Salk.

About the Salk Institute for Biological Studies:

Every cure has a starting point. The Salk Institute embodies Jonas Salk's mission to dare to make dreams into reality. Its internationally renowned and award-winning scientists explore the very foundations of life, seeking new understandings in neuroscience, genetics, immunology, plant biology and more. The Institute is an independent nonprofit organization and architectural landmark: small by choice, intimate by nature and fearless in the face of any challenge. Be it cancer or Alzheimer's, aging or diabetes, Salk is where cures begin. Learn more at: salk.edu.

Media Contact

Salk Communications
press@salk.edu
858-453-4100

 @salkinstitute

http://www.salk.edu 

Salk Communications | EurekAlert!

Further reports about: PNAS algorithm computer science fruit fly machine learning neurons odors waste time

More articles from Life Sciences:

nachricht Researchers find new mutation in the leptin gene
24.06.2019 | Texas Biomedical Research Institute

nachricht Straight to the heart
24.06.2019 | Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz-Gemeinschaft

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fraunhofer IDMT demonstrates its method for acoustic quality inspection at »Sensor+Test 2019« in Nürnberg

From June 25th to 27th 2019, the Fraunhofer Institute for Digital Media Technology IDMT in Ilmenau (Germany) will be presenting a new solution for acoustic quality inspection allowing contact-free, non-destructive testing of manufactured parts and components. The method which has reached Technology Readiness Level 6 already, is currently being successfully tested in practical use together with a number of industrial partners.

Reducing machine downtime, manufacturing defects, and excessive scrap

Im Focus: Successfully Tested in Praxis: Bidirectional Sensor Technology Optimizes Laser Material Deposition

The quality of additively manufactured components depends not only on the manufacturing process, but also on the inline process control. The process control ensures a reliable coating process because it detects deviations from the target geometry immediately. At LASER World of PHOTONICS 2019, the Fraunhofer Institute for Laser Technology ILT will be demonstrating how well bi-directional sensor technology can already be used for Laser Material Deposition (LMD) in combination with commercial optics at booth A2.431.

Fraunhofer ILT has been developing optical sensor technology specifically for production measurement technology for around 10 years. In particular, its »bd-1«...

Im Focus: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on UV LED Technologies & Applications – ICULTA 2020 | Call for Abstracts

24.06.2019 | Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

 
Latest News

2nd International Conference on UV LED Technologies & Applications – ICULTA 2020 | Call for Abstracts

24.06.2019 | Event News

'Sneezing' plants contribute to disease proliferation

24.06.2019 | Agricultural and Forestry Science

Researchers find new mutation in the leptin gene

24.06.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>